Fast4525

On a 951S with cat bypass and Vitesse chip + MBC @ 16psi what benefit will I see from switching to a TiAL 38mm WG?

I have read that the TiAL can improve boost response and reduce the amount of boost taper above 5500rpm. Is the original WG that bad

elargentino

Yes, it is terrible.
It is not so much a wastegate, as a safety valve.
I have never seen another real wastegate where the valve opens outward, with backpressure.
The Tial totally transforms the car.

CyCloNe!

generally the factory wastegate is old so the spring is worn and weak after 20+ years. Also the factory wastgate was built for roughly 10-11psi and made to hold roughly 13psi. So when you hit near redline your 16psi you have it set to will drop down to the 13psi range. By upgrading to a new wastegate, like tial, you then will be able to hold your 16psi to redline which means you are keeping 3 psi. 3psi depending on your turbo could be 20+ hp.

So if you can get an upgrade then you would benefit greatly in your higher rpms.

MooreBoost

if you shim the stock wg it will be just fine. i shimmed my stock wg and was holding 20psi till 5500 rpms. you only have 900 rpms left to go. so the question is do you want to spend the money on a new wg for 900 more rpms

CyCloNe!

you can talk to teamcrossworks he sells rebuild units that hold 15psi for 200 bucks... that combined with shims would be good, atleast you would have a cough* newish unit. I have one and I can say it does work great, completely worth the money.

teamcrossworks

Thanks for the kind words Conrad.

Always available...free Wastegate Rebuild write-up (word doc.) if you PM me with your E-Mail address to anyone interested. Not too hard and the benefits are definitely worthwhile!

TurboTommy

There's nothing wrong with that.
It keeps back pressure in check. It increases part throttle power. It costs a little in spool-up, but I'd rather make up for that with lowest intake and exhaust restrictions as possible; that's the healthier way of doing it.

To the OP;
should upgrade the turbo first, to ensure that the turbo can flow the additional air (which the aftermarket wastegate is forcing it to do) efficiently.
If you're concerned about the age of your unit: test it (clarks garage); for additional performance: shim it (like already stated), and/or put an LBE in front of it.

blade7

I keep thinking I about replacing my original wastegate but with some tweaking it makes 15 psi by around 3k and seems to hold it to the redline so would I really gain much ?.

superloaf

yeah, i have a similar question: we all know the stock WG falls off at higher revs but will the tial improve performance at lower revs? in other words, is the tial better in lessening lag or bringing boost on stronger? what about when i already have a shimmed gate and a LBE?

thanks

MooreBoost

if you are running less then 16 psi and have a shimmed stock wg it should hold 16 psi to redline. the moore boost you add the stronger wg u need. when i was boosting 16 psi on my stock shimmed wg it would hold 16 psi till redline

teamcrossworks

Just to add my .02 cents...

The stock wastegate suffers from two distict problems after 20+ years; the spring has lost some of it's "stiffness" and the seal between the body and valve has been compromised.

To install a shim is a quick fix for the spring although pre-loading a spring is not the same as stiffening it's rate. IMOH, changing it is the better solution.

Anyone that has not done so already can improve their wastegate's performance by "lapping" the valve seat to improve it's seal. Almost all the wastegates I've worked on began to leak around the valve seat before the spring ever came into play.

Euro951

I felt no difference between running a stock WG with a boost controller and a Tial 38mm. But then again I am only running 11-12lbs of boost. Although your experience may be different, my stock WG was in excellent condition.

Willard Bridgham 3

My stock wastegate, unshimmed, held 18 psig for 150 track hours. Fixing the stock unit is certainly a good option.

Boost pressure fall off in the upper RPM range for the stock turbo is a function of the turbo design.

Fast4525

Typical forum thread


Some say the stock WG is a poor design and some say it is a great design.

Some say I will see performance benefits from "upgrading" to a TiAL and others say it won't make any difference.





At $400 it won't be the most expensive paperweight I have ever bought!

MooreBoost

IMO buy a maf before a wastegate